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authorTom Zanussi <tom.zanussi@linux.intel.com>2018-01-15 20:52:03 -0600
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2018-03-10 16:06:01 -0500
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tracing: Add cpu field for hist triggers
A common key to use in a histogram is the cpuid - add a new cpu 'synthetic' field named 'cpu' for that purpose. Link: http://lkml.kernel.org/r/89537645bfc957e0d76e2cacf5f0ada88691a6cc.1516069914.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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-rw-r--r--Documentation/trace/histogram.txt15
1 files changed, 15 insertions, 0 deletions
diff --git a/Documentation/trace/histogram.txt b/Documentation/trace/histogram.txt
index 25c94730d3fe..be612ca79455 100644
--- a/Documentation/trace/histogram.txt
+++ b/Documentation/trace/histogram.txt
@@ -172,6 +172,21 @@
The examples below provide a more concrete illustration of the
concepts and typical usage patterns discussed above.
+ 'special' event fields
+ ------------------------
+
+ There are a number of 'special event fields' available for use as
+ keys or values in a hist trigger. These look like and behave as if
+ they were actual event fields, but aren't really part of the event's
+ field definition or format file. They are however available for any
+ event, and can be used anywhere an actual event field could be.
+ They are:
+
+ common_timestamp u64 - timestamp (from ring buffer) associated
+ with the event, in nanoseconds. May be
+ modified by .usecs to have timestamps
+ interpreted as microseconds.
+ cpu int - the cpu on which the event occurred.
6.2 'hist' trigger examples
---------------------------